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Local Hazards

Auburn is subject to a wide variety of natural and technological disasters. Everyone should become familiar with the hazards that can affect their specific area and take steps to prepare for them. A brief overview of common hazards is presented below, but you can find in-depth descriptions and analysis in our Hazard Mitigation Plan (PDF) which is an annex to the 2009 King County Regional Hazard Mitigation Plan.

Drought

Drought is an extended period (usually one or more seasons) of abnormally low precipitation. In Washington State, the criteria for drought is that the water supply for an area be below 75% of normal and that the water shortage is likely to create hardships for the people who rely on it. The City gets its water from multiple sources, which greatly insulates us from water emergencies. Even when drought conditions have been declared in King County in the past, Auburn has not had severe impacts, due either to our use of multiple water sources or to voluntary conservations measures on the part of residents and businesses. It would be unusual for Auburn to experience a drought that does not also affect the rest of the region, however we do experience water shortages from time-to-time that cause us to put our Water Shortage Emergency Plan into action. The Water Shortage Emergency Plan has five levels, ranging from voluntary conservation to enforced reductions. The City has never had to go beyond a Stage 1, which calls for voluntary reductions.

Excessive Heat

Excessive Heat is categorized as periods of significantly higher than average temperatures, most commonly seen during the summer months for short periods of time. Microclimatic fluctuations allow for conditions of excessive heat to be limited to a smaller regional area, although it is possible that broader areas may be affected. In the Seattle area, daytime temperatures that reach into the 90s or greater are considered a problem, particularly when nighttime temperatures do not drop below the 60s. We typically see one or two periods each summer that fall into the excessive heat category. The National Weather Service establishes the criteria for Excessive Heat Watches/Warnings based on temperature, humidity, and mortality statistics, and the current criteria were adopted in 2005. Since then, there have three periods of excessive heat. Though no deaths have occurred in Auburn due to this, 3-4 people typically die each year in the Seattle area due to excessive heat. The elderly, as well as children under 4 years of age, are most vulnerable. The City provides cooling centers to the public during Excessive Heat Warnings.

Earthquake

An earthquake is the sudden release of stored energy in the earth's crust or between two continental plates that produces a rapid displacement on a fault and radiate seismic waves. Occasionally, large earthquakes produce very strong ground shaking. It is this strong shaking and its cascading consequences – ground failure, landslides, liquefaction – that damages buildings and structures and upsets the regional economy.

Auburn, as part of the Puget Sound region, is at a convergent margin between two tectonic plates of the Earth's crust. Two converging plates create a complicated system of three distinct earthquake source zones; the Cascadia subduction zone (produces great earthquakes approximately every 500 years), the Benioff (or Deep) Zone (the area near the Juan de Fuca plate that subducts beneath North America and the most frequent source of damaging earthquakes for Puget Sound); and the Crustal Zone. Since 2000, geologists have discovered over 12 active crustal faults in Puget Sound, but few are documented in other parts of the state. The probability of a significant earthquake occurring the Puget Sound region is high. Auburn is at particular risk in an earthquake due to the alluvial soils present in the Green River Valley. These soils can liquify during an earthquake, causing significant ground disruption (in addition to what is caused from the actual earthquake). Ground disruption can damage or destroy roads, bridges, utilities, and buildings. A large earthquake would cause damage throughout the region, further disrupting life in our City. There have been 20 damaging earthquakes in the last 125 years, with the most recent being the Nisqually earthquake in 2001. This earthquake caused damaged to older masonry buildings in downtown Auburn, as well as to brick and masonry structures throughout the community.

The City has taken a variety of steps to mitigate potential damage from Earthquakes. Chief among these steps has been the adoption of the International Building Code, including seismic standards appropriate for the greater Puget Sound region. Earthquake retrofits have been completed on some key facilities and all City facilities occupied by people have been reviewed for earthquake safety hazards.

Floods

Flooding in King and Pierce Counties occurs primarily when large, wet and warm weather systems occur in the Cascade Mountains and after snow packs have accumulated. The combination of melting snow runoff and added rain fills rivers within hours and usually builds over one to three days. Most flooding occurs in the winter months, typically from November through February. Flooding frequently affects the low position in the landscape and thus is more likely to affect the valley floor portion of Auburn, especially near creeks and rivers.

Flooding occurs primarily along the Green and White rivers, in low elevation areas throughout the City. River flooding is controlled by upstream dams on both the Green (Howard Hanson Dam) and White (Mud Mountain Dam) rivers, so significant flooding is only expected to occur during very high precipitation events. Areas along the river channel will be affected at low levels of flooding, but much of northern Auburn is susceptible to inundation at higher flood stages. Flooding peaks with heavy rain events, but once precipitation ceases there is a lag period while groundwater drains and floodwaters recede. Minor street flooding related to clogged or slow storm drains happens on a nearly annual basis. The City has not experienced significant flooding since the dams were built.

The National Weather Servicelinks to external site is responsible for establishing flood levels for area rivers, as well as for issuing flood watches and warnings for those rivers. King County Department of Natural Resources offers several flood alert systems which rebroadcast National Weather Service information. Those systems can be found on their websitelinks to external site.  The City of Auburn offers an additional layer of flood notification by rebroadcasting warnings using our CodeRed system, which utilizes phone, text, and e-mail notices. In the event of a flood, the City will utilize some portion of the established lahar/volcano evacuation routes as our flood routes. Each evacuation situation is evaluated individually to ensure proper evacuation support, including sheltering. The entire evacuation and sheltering plan is included in the City's Comprehensive Emergency Management Plan (CEMP) (PDF). It is important to note that though the City has established agreements for a large number of emergency shelter locations, both inside and outside the City, those locations are not published in advance due to confidentiality and to ensure that citizens do not attempt to utilize a shelter that is not open. As with all other emergencies, citizens should monitor established media channels, including AM 1700, and follow instructions provided there and via the CodeRed system.

If a moderate to severe flood were to occur along the Green River, approximately 10,000 residents might be directly impacted, along with more than 400 businesses. A flood of the Green River would have a significant economic impact on not just the City, but the entire region, predominantly for neighboring cities along the Green River.

City residents and businesses are eligible for reduced cost flood insurance through the National Flood Insurance Program (NFIP). Visit www.floodsmart.gov to find out if your home or business is in a special flood hazard area, to get a quote for flood insurance, or to find a specially trained flood insurance agent.  For flood preparedness tips specific to the Puget Sound region, visit the Make It Through campaign's Flood websitelinks to external site.

Landslide

The term landslide includes a wide range of ground movement, such as rock falls, deep failure of slopes, and shallow debris flows. Several small landslides are recorded each winter in Auburn, typically following heavy rain events. Generally, these small landslides are a nuisance for drivers, as they often temporarily block roadways. Occasionally a landslide will occur that damages underground pipes and other infrastructure, which may have a greater impact.

Severe Weather

Severe weather can include above average amounts of rain, snow or ice, extreme temperatures, high winds, and thunderstorms. Severe winter weather is often accompanied by heavy rains and flooding conditions. Severe weather can happen at any time of year though. Unusual rain, snow, ice, extreme cold and high winds usually occurs between October and April. In the summer months, extreme weather takes the form of excessive heat and thunderstorms.

January 2012 saw a severe winter storm hit the Puget Sound region, with snow, wind, and extensive ice. Extensive damage to trees and other vegetation was experienced throughout Auburn and power was out in some neighborhoods for 6 days. Regional shelters were opened for those who needed assistance. A large debris removal effort was undertaken, with drop sites setup throughout the community for vegetation debris, as well as extra curbside collection for residential customers. The total cost of this storm to the City was more than half a million dollars.

The City has focused on public education and response planning to mitigate the effects of severe weather. NOAA weather radios have been placed in all City facilities and the City was awarded NWS StormReady status in 2010.

Volcano

The volcano posing the most significant risk to Auburn is Mount Rainier, which sits approximately 40 miles southeast of the city limits. Mt. Rainier has not shown any signs of increased activity, however that can change at any time. The greatest threat to Auburn associated with volcanic activity is a lahar (mudflow). A lahar is a type of mudflow composed of pyroclastic material and water that flows down slope from a volcano, typically along a river valley. Auburn is potentially within the path of a lahar, should one occur, but given the infrequent nature of this hazard, it is difficult to determine the exact impacts that might occur in the City. If a lahar were to travel down the Green River however, it would reach Auburn in approximately 1.6 hours, requiring the rapid evacuation of the valley area of the City.

In 2006, the City established a lahar evacuation plan and posted volcano evacuation signs in areas of the City that might be subjected to lahar evacuations. These signs direct the route to high ground, above the presumed highest potential levels of the lahar flow.  USGS volcano monitoring also acts as an early-warning system to prepare the City for the possibility of evacuation. View a map of lahar evacuation routes (PDF).

Wildland/Urban Interface Fire

A wildland/urban interface area is the geographic area where structures and other human development meets or intermingles with wildland or vegetative fuels. A wildland/urban interface fire is a fire located in that geographic area. There are several locations within Auburn where structural developments meet and intermingle with the wildland areas. This condition gives rise to the possibility of interface fires especially when weather conditions are dry and fuels are abundant. Though there has never been an interface fire in Auburn, homeowners in forested areas should make every effort to create defensible space around their homes.

Dam Issues

A dam failure or malfunction is any situation relating to the safety and operation of a dam. Currently Howard Hanson, Mud Mountain, Lakeland South Pond, Lake Youngs Reservoir and Lake Tapps dams could impact the City if they experienced a failure or malfunction. In 2009, significant seepage issues were discovered the Howard Hanson Dam, which provides flood protection for the Green River. Repairs were rapidly made to this dam by the US Army Corps of Engineers and it is currently operating normally.

Hazardous Materials Release

Hazardous Materials include any substance which can cause notable damage to people, the environment, or property. Typically a release event would be from industrial or transportation accidents, although purposeful releases through terrorism or emergency venting of chemicals to prevent a larger scale catastrophe can occur as well. Hazardous materials move through the Auburn region on highways, rail lines, and pipelines and are stored in fixed facilities throughout the City. Each facility that uses hazardous materials is required to maintain plans for warning, notification, evacuation, and site security under various regulations. Release of hazardous materials can happen at either a source point, such as a production facility, or during transportation. This limits exposure for most chemical releases to major transportation routes and facilities that use, produce, or dispose of hazardous materials. However, broader contamination is possible if the hazardous material is gaseous or volatile, or is spilled near a secondary means of conveyance such as a storm drain.

Tracking the history of hazardous materials releases is difficult, as many go unreported or are too minor to warrant immediate response. Large or dangerous releases, which must be reported immediately, are uncommon. The most serious event in recent history was a toxic cloud accidentally released from a local manufacturer in 1995, which required the evacuation of 12 buildings and resulted in a number of hospitalizations, though no fatalities or serious injuries.

If you have questions about any of these hazards or about emergency preparedness, please contact our office at 253-876-1925 or email us.